To incorporate an integrated circuit package into an electronic system, the integrated circuit is typically connected to a printed circuit board or similar element through which the integrated circuit package can communicate with other components of the system. The integrated circuit package can include one or more electrically conductive contact pads while the printed circuit board can include conductive traces. Often, the contact pads and conductive traces are arranged in corresponding patterns referred to as Land Grid Arrays (“LGA's”). Electrical communication between the contact pads and the conductive traces is typically achieved by placing an electrical connector between the integrated circuit package and the printed circuit board.
Interposer assemblies, as will be familiar to those of skill in the art, typically include an insulative housing or similar structure that can accommodate a plurality of electrically conductive contacts. The contacts are commonly held in holes disposed through the housing. To maximize the number of contacts that can be accommodated, the holes are often densely packed together. Furthermore, the interposer assembly desirably should accommodate the conductive contacts so that the contacts are aligned with the LGA's on the integrated circuit package and the printed circuit board, an attribute that requires precise alignment of the holes within the housing.
To reduce the cost of the interposer assembly, the housing is preferably made from molded plastic. Of course, to fabricate the housing with the precise alignment required, precision molding machines are needed. Such machines have thus far been capable of producing interposer assemblies of moderate sizes.
Because of the advances in integrated circuit technology, the number of communication paths that must be established between the integrated circuit package and the rest  of the system, and thus accordingly the number of electrical contacts required in the interposer assembly has increased dramatically. To accommodate more contacts in the already densely packed interposer assembly, the overall dimensions of the interposer assembly have gradually increased. Increasing the size of the interposer assembly, however, generates a problem with injection molding the housing.
More specifically, with molded plastics a phenomenon known as shrinkage occurs whereby the plastic contracts upon itself as it cools after molding thereby distorting the finished part. The effects of shrinkage are minimal when only a small volume of plastic is molded to make a part. Increasing the amount of plastic though, as is necessary to increase the size of the housing for the larger interposer assemblies, exacerbates the shrinkage problem and sacrifices the precision needed to densely pack and align the contacts.